22.2. Action State

An action state represents execution of an atomic action,
usually the invocation of an action. Within the UML metamodel,
ActionState is a sub-class of
SimpleState. It is a specialized simple state that only has
an entry action, and with an implicit trigger as soon as that action
is completed.

Caution

As a consequence any outgoing transitions from an action state
should not have explicit triggers defined (ArgoUML will not
currently check for this). They may have guards to provide a choice
where there is more than one transition.

Note

Unlike an ordinary state, an internal transition, an exit
action and a Do activity are not permitted for action states.

An action state is represented on an activity diagram in ArgoUML
as a rectangle with rounded corners containing the name of the action
state.

Caution

The UML standard specifies that the text shown in the action
state on the activity diagram should contain the expression
associated with the entry action - which is implemented as such
since ArgoUML V0.18. In past versions of ArgoUML (0.16.1 and
before), the diagram used to show the action state name. Loading a
project created by one of the older versions, causes the project
file to be converted to the correct format to conform to the UML
standard. This process is designed to be transparent for the user,
and the only drawback is, that the activity diagram in the project
will not show correctly when reloaded in an old version of ArgoUML
again.